There are different versions for various KM versions. One of the things this extension does is add "Title Bar" to the VIEW menu. It is an ON/OFF toggle. It also adds a toolbar with normal title bar controls.

Yes，I had found that extension.But I will use the fullscreen model,because I don't want to install too much extensions,maybe those would affect the speed or memory usage of the K-Meleon.
Thanks,you and snuz2.